A CAMPBELL–STOKES SUNSHINE RECORDER BY CASELLA OF LONDON. CIRCA 1968.
Marked with the Casella logo. Numbered: 8977.
The Campbell–Stokes sphere is used to record sunshine.
Height: 23 cm.
Width: 19.5 cm.
Depth: 20 cm.
On a later hardwood display board. 23 cm x 23 cm.
It was invented by John Francis Campbell in 1853 and modified in 1879 by Sir George Gabriel Stokes.
The original design by Campbell consisted of a glass sphere set into a wooden bowl with the sun burning a trace on the bowl.
Stokes’s refinement was to make the housing out of metal and to have a card holder set behind the sphere.